'Rashi': Had you relied on Hashem, like in the war against the Kushim, (a) you would not have lost your money, and (b) you would have conquered all of them. Now that you did not rely on Hashem, you lost your money, and Melech Aram escaped from you. Malbim - Hashem arranged that Aram come with Basha in order to hand them over to you!